Feedback based on designated subset of codebook

Abstract

The present invention provides for an improved application of signal strength weightings in a SDMA sectorized cellular network. The improved signal strength weightings application is conducted through the improved selection of weightings from a new codebook subset or by the selection of weightings from a larger codebook subset. In a further embodiment, an antenna beam index or bit map can be used to select the best beam(s) in a SDMA sectorized cellular network. In another embodiment, a field or factor in an uplink or downlink transmission packet can designate which directional transmission beam is best suited for the transmission or when the directional transmission beam should be activated.

What is claimed is: 
     
       1. A method for operating a user equipment (UE) device, to facilitate communication with a base station, the method comprising:
 transmitting, by a transmitter of the UE device, a codeword index to the base station, wherein the codeword index identifies a first codebook weighting matrix from within a designated subset of a codebook, wherein the codebook includes at least six codebook weighting matrices, wherein each of the codebook weighting matrices includes one or more layer-related columns, wherein each of the layer-related columns includes a plurality of complex weight values having absolute value less than or equal to one; 
 receiving, by a receiver of the UE device, signals from a channel, wherein the signals have been generated by a precoding operation based on a particular codebook weighting matrix from the designated subset; and 
 recovering, by the receiver, information from the received signals. 
 
     
     
       2. The method of  claim 1 , wherein the codeword index is a 2-bit index. 
     
     
       3. The method of  claim 1 , further comprising:
 receiving a downlink index from the base station, wherein the downlink index identifies the particular codebook weighting matrix from within the designated subset of the codebook. 
 
     
     
       4. The method of  claim 1 , wherein the complex weight values of the codebook weighting matrices in the designated subset have constant modulus. 
     
     
       5. The method of  claim 1 , wherein the particular codebook weighting matrix is different from the codebook weighting matrix identified by the codeword index. 
     
     
       6. The method of  claim 1 , wherein the at least six codebook weighting matrices include a scaled identity matrix, wherein the designated subset does not include the scaled identity matrix. 
     
     
       7. The method of  claim 1 , wherein the designated subset consists of six codebook weighting matrices, wherein the complex weight values of the six codebook weighting matrices have constant modulus. 
     
     
       8. The method of  claim 1 , further comprising:
 transmitting subset selection bits to the base station, wherein the subset selection bits indicate a selection of the designated subset from the codebook. 
 
     
     
       9. An apparatus for communication with a base station, the apparatus comprising circuitry configured to implement:
 transmitting a codeword index to the base station, wherein the codeword index identifies a first codebook weighting matrix from within a designated subset of a codebook, wherein the codebook includes at least six codebook weighting matrices, wherein each of the codebook weighting matrices includes one or more layer-related columns, wherein each of the layer-related columns includes a plurality of complex weight values having absolute value less than or equal to one; 
 receiving signals from a channel, wherein the signals have been generated by a precoding operation based on a particular codebook weighting matrix from the designated subset; and 
 recovering information from the received signals. 
 
     
     
       10. The apparatus of  claim 9 , wherein the codeword index is a 2-bit index. 
     
     
       11. The apparatus of  claim 9 , wherein the circuitry is further configured to implement:
 receiving a downlink index from the base station, wherein the downlink index identifies the particular codebook weighting matrix from within the designated subset of the codebook. 
 
     
     
       12. The apparatus of  claim 9 , wherein the complex weight values of the codebook weighting matrices in the designated subset have constant modulus. 
     
     
       13. The apparatus of  claim 9 , wherein the particular codebook weighting matrix is different from the codebook weighting matrix identified by the codeword index. 
     
     
       14. The apparatus of  claim 9 , wherein the at least six codebook weighting matrices include a scaled identity matrix, wherein the designated subset does not include the scaled identity matrix, wherein the designated subset consists of six codebook weighting matrices, wherein the complex weight values of the six codebook weighting matrices have constant modulus. 
     
     
       15. A non-transitory memory medium for communication with a base station, wherein the non-transitory memory medium stores program instructions, wherein the program instructions, when executed by a processor, cause the processor to implement:
 transmitting a codeword index to the base station, wherein the codeword index identifies a first codebook weighting matrix from within a designated subset of a codebook, wherein the codebook includes at least six codebook weighting matrices, wherein each of the codebook weighting matrices includes one or more layer-related columns, wherein each of the layer-related columns includes a plurality of complex weight values having absolute value less than or equal to one; 
 receiving signals from a channel, wherein the signals have been generated by a precoding operation based on a particular codebook weighting matrix from the designated subset; and 
 recovering information from the received signals. 
 
     
     
       16. The non-transitory memory medium of  claim 15 , wherein the codeword index is a 2-bit index. 
     
     
       17. The non-transitory memory medium of  claim 15 , wherein the program instructions, when executed by the processor, further cause the processor to implement:
 receiving a downlink index from the base station, wherein the downlink index identifies the particular codebook weighting matrix from within the designated subset of the codebook. 
 
     
     
       18. The non-transitory memory medium of  claim 15 , wherein the complex weight values of the codebook weighting matrices in the designated subset have constant modulus. 
     
     
       19. The non-transitory memory medium of  claim 15 , wherein the particular codebook weighting matrix is different from the codebook weighting matrix identified by the codeword index. 
     
     
       20. The non-transitory memory medium of  claim 15 , wherein the at least six codebook weighting matrices include a scaled identity matrix, wherein the designated subset does not include the scaled identity matrix, wherein the designated subset consists of six codebook weighting matrices, wherein the complex weight values of the six codebook weighting matrices have constant modulus.